This species hybridizes with M. tonkeana and possibly with M. nigrescens in areas where their ranges overlap. These hybrid zones, however, appear to be disappearing owing to human encroachment (M. Richardson pers. comm.).

Justification:
This species is listed as Vulnerable due to its continuing decline and future population declines estimated be > 30% over the next 40 years (i.e., three generations), as estimated by current rates of habitat conversion and increasing human population densities.

Very little is known of the populations of this species. Densities are estimated to be 20-50 individuals/km2, with group sizes of approximately 10-20 (Supriatna and Hendras 2000). Density is 6.0 individuals/km2 in forest areas (WCS unpubl. data).

Very little is known of the habitat and ecology of this species (this is one of the least studied of the Sulawesi macaques). It is presumably diurnal and frugivorous, semi-arboreal and occurs in primary and secondary tropical rainforest.

The greatest threat to the species is loss of habitat, which is increasingly fragmented. Additionally, the species is captured, poisoned, shot and persecuted by local farmers who consider the animals crop raiders.

This species is listed under CITES Appendix II. It is known to occur in at least 6 protected areas: Dolangan Reserve, Mas Popaya Raja Reserve, Panua Reserve, Pangi Binanga Reserve, Pinjam/Tanjung Mantop Reserve, Tangale Reserve (M. Richardson pers. comm.). There is a need to expand existing protected areas. There are no specimens reported in captivity.

In-Place Research, Monitoring and PlanningIn-Place Land/Water Protection and Management Occur in at least one PA:YesIn-Place Species ManagementIn-Place Education Included in international legislation:Yes Subject to any international management/trade controls:Yes

Watanabe, K. and Matsumura, S. 1991. The borderlands and possible hybrids between three species of macaques, M. nigra, M. nigriscens, and M. hecki, in the northern peninsula of Sulawesi. Primates 32(3): 365-369.

Watanabe, K., Lapasere, H. and Tantu, R. 1991. External characteristics and associated developmental changes in two species of Sulawesi macaques, Macaca tonkeana and M. hecki, with special reference to hybrids and the borderland between the species. Primates 32(1): 61-76.